In an optical network, optical circuits are typically set up between pairs of end points. The equipment at both ends needs to be configured in a consistent fashion in order to be compatible and enable the successful transfer of information. While in service, both end points need to have their performance monitored so that the service can be properly managed. Both these actions (configuring and managing) become difficult if those end points are provided by different vendors because each vendor has its own management system. Additionally, there may be difficulty physically accessing one or both ends if they are remote from the management entity. If it exists, a separate communications path to reach the remote end point will have security issues associated with it. These problems become more complicated in the case of Wavelength Division Multiplexed (WDM) optical networks.
WDM circuits originate and terminate at a WDM transceiver function. The transceiver converts electrical signals into optical signals using a laser and back from optical to electrical using a photodetector. In the case of signals that are intended to go through ROADMs, there is generally an Optical Transport Network (OTN) framer with Forward Error Correction (FEC) capability associated with the WDM transceiver. In this instance, it is important to consider the two together so this combination is referred to as “OTN and WDM transceiver functions”.
There are complex interactions between the OTN & WDM transceiving function and optical network elements such as Reconfigurable Optical Add/Drop Multiplexors (ROADMs), containing switching, amplification and dispersion compensation functions, which make it important for the system managing the end to end optical circuit to have detailed information about all aspects. For this reason, it has been common industry practice for the ROADM and OTN and WDM transceiver line cards to be supplied from the same vendor. This practice requires third party equipment to connect to the WDM network using additional optical-to-electrical-to-optical conversion steps to access the OTN and WDM transceiver line card. Such steps add complexity and cost.
There have been attempts to place the OTN and WDM transceiver directly on the third party equipment. In an ‘alien wavelength’ approach, the ROADM and associated management system does not communicate with the end OTN and WDM transceiver functions so there is no management of the end-end optical link. Another alternative is to have a physical communications path between the management system and the end points that is separate from the fibers over which the end-end lightpath is set up for the exchange of user information. The current invention proposes a means to be able to remotely configure and manage WDM transceivers located in third party equipment by communicating over the same fiber used for information transfer.